ip6_forward.c revision 122062
162587Sitojun/* $FreeBSD: head/sys/netinet6/ip6_forward.c 122062 2003-11-04 16:02:05Z ume $ */ 278064Sume/* $KAME: ip6_forward.c,v 1.69 2001/05/17 03:48:30 itojun Exp $ */ 362587Sitojun 453541Sshin/* 553541Sshin * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 653541Sshin * All rights reserved. 753541Sshin * 853541Sshin * Redistribution and use in source and binary forms, with or without 953541Sshin * modification, are permitted provided that the following conditions 1053541Sshin * are met: 1153541Sshin * 1. Redistributions of source code must retain the above copyright 1253541Sshin * notice, this list of conditions and the following disclaimer. 1353541Sshin * 2. Redistributions in binary form must reproduce the above copyright 1453541Sshin * notice, this list of conditions and the following disclaimer in the 1553541Sshin * documentation and/or other materials provided with the distribution. 1653541Sshin * 3. Neither the name of the project nor the names of its contributors 1753541Sshin * may be used to endorse or promote products derived from this software 1853541Sshin * without specific prior written permission. 1953541Sshin * 2053541Sshin * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 2153541Sshin * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2253541Sshin * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2353541Sshin * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 2453541Sshin * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2553541Sshin * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2653541Sshin * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2753541Sshin * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2853541Sshin * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2953541Sshin * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3053541Sshin * SUCH DAMAGE. 3153541Sshin */ 3253541Sshin 3362587Sitojun#include "opt_ip6fw.h" 3462587Sitojun#include "opt_inet.h" 3562587Sitojun#include "opt_inet6.h" 3655009Sshin#include "opt_ipsec.h" 37120386Ssam#include "opt_pfil_hooks.h" 3853541Sshin 3953541Sshin#include <sys/param.h> 4053541Sshin#include <sys/systm.h> 4178064Sume#include <sys/malloc.h> 4253541Sshin#include <sys/mbuf.h> 4353541Sshin#include <sys/domain.h> 4453541Sshin#include <sys/protosw.h> 4553541Sshin#include <sys/socket.h> 4653541Sshin#include <sys/errno.h> 4753541Sshin#include <sys/time.h> 4878064Sume#include <sys/kernel.h> 4953541Sshin#include <sys/syslog.h> 5053541Sshin 5153541Sshin#include <net/if.h> 5253541Sshin#include <net/route.h> 5384994Sdarrenr#ifdef PFIL_HOOKS 5484994Sdarrenr#include <net/pfil.h> 5584994Sdarrenr#endif 5653541Sshin 5753541Sshin#include <netinet/in.h> 5853541Sshin#include <netinet/in_var.h> 5978064Sume#include <netinet/in_systm.h> 6078064Sume#include <netinet/ip.h> 6162587Sitojun#include <netinet/ip_var.h> 6278064Sume#include <netinet6/in6_var.h> 6362587Sitojun#include <netinet/ip6.h> 6453541Sshin#include <netinet6/ip6_var.h> 6562587Sitojun#include <netinet/icmp6.h> 6653541Sshin#include <netinet6/nd6.h> 6753541Sshin 6878064Sume#include <netinet/in_pcb.h> 6978064Sume 7063256Sitojun#ifdef IPSEC 7153541Sshin#include <netinet6/ipsec.h> 7278064Sume#ifdef INET6 7362601Sitojun#include <netinet6/ipsec6.h> 7478064Sume#endif 7553541Sshin#include <netkey/key.h> 7663256Sitojun#endif /* IPSEC */ 7753541Sshin 78105199Ssam#ifdef FAST_IPSEC 79105199Ssam#include <netipsec/ipsec.h> 80105199Ssam#include <netipsec/ipsec6.h> 81105199Ssam#include <netipsec/key.h> 82105199Ssam#define IPSEC 83105199Ssam#endif /* FAST_IPSEC */ 84105199Ssam 8553541Sshin#include <netinet6/ip6_fw.h> 8653541Sshin 8753541Sshin#include <net/net_osdep.h> 8853541Sshin 8984994Sdarrenr#include <netinet6/ip6protosw.h> 9084994Sdarrenr 9153541Sshinstruct route_in6 ip6_forward_rt; 9253541Sshin 9353541Sshin/* 9453541Sshin * Forward a packet. If some error occurs return the sender 9553541Sshin * an icmp packet. Note we can't always generate a meaningful 9653541Sshin * icmp message because icmp doesn't have a large enough repertoire 9753541Sshin * of codes and types. 9853541Sshin * 9953541Sshin * If not forwarding, just drop the packet. This could be confusing 10053541Sshin * if ipforwarding was zero but some routing protocol was advancing 10153541Sshin * us as a gateway to somewhere. However, we must let the routing 10253541Sshin * protocol deal with that. 10353541Sshin * 10453541Sshin */ 10553541Sshin 10653541Sshinvoid 10753541Sshinip6_forward(m, srcrt) 10853541Sshin struct mbuf *m; 10953541Sshin int srcrt; 11053541Sshin{ 11153541Sshin struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *); 112122062Sume struct sockaddr_in6 *dst = NULL; 113122062Sume struct rtentry *rt = NULL; 11453541Sshin int error, type = 0, code = 0; 11562587Sitojun struct mbuf *mcopy = NULL; 11662587Sitojun struct ifnet *origifp; /* maybe unnecessary */ 117121315Sume u_int32_t srczone, dstzone; 11863256Sitojun#ifdef IPSEC 11953541Sshin struct secpolicy *sp = NULL; 120122062Sume int ipsecrt = 0; 12153541Sshin#endif 12253541Sshin 12363256Sitojun#ifdef IPSEC 12453541Sshin /* 12553541Sshin * Check AH/ESP integrity. 12653541Sshin */ 12753541Sshin /* 12853541Sshin * Don't increment ip6s_cantforward because this is the check 12953541Sshin * before forwarding packet actually. 13053541Sshin */ 13153541Sshin if (ipsec6_in_reject(m, NULL)) { 132105199Ssam#if !defined(FAST_IPSEC) 13353541Sshin ipsec6stat.in_polvio++; 134105199Ssam#endif 13553541Sshin m_freem(m); 13653541Sshin return; 13753541Sshin } 13895023Ssuz#endif /* IPSEC */ 13953541Sshin 14078064Sume /* 14178064Sume * Do not forward packets to multicast destination (should be handled 14278064Sume * by ip6_mforward(). 14378064Sume * Do not forward packets with unspecified source. It was discussed 144120913Sume * in July 2000, on the ipngwg mailing list. 14578064Sume */ 14662587Sitojun if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 || 14778064Sume IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) || 14878064Sume IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) { 14953541Sshin ip6stat.ip6s_cantforward++; 15053541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 15153541Sshin if (ip6_log_time + ip6_log_interval < time_second) { 15253541Sshin ip6_log_time = time_second; 15353541Sshin log(LOG_DEBUG, 15453541Sshin "cannot forward " 15553541Sshin "from %s to %s nxt %d received on %s\n", 15662587Sitojun ip6_sprintf(&ip6->ip6_src), 15762587Sitojun ip6_sprintf(&ip6->ip6_dst), 15853541Sshin ip6->ip6_nxt, 15953541Sshin if_name(m->m_pkthdr.rcvif)); 16053541Sshin } 16153541Sshin m_freem(m); 16253541Sshin return; 16353541Sshin } 16453541Sshin 16553541Sshin if (ip6->ip6_hlim <= IPV6_HLIMDEC) { 16653541Sshin /* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */ 16753541Sshin icmp6_error(m, ICMP6_TIME_EXCEEDED, 16853541Sshin ICMP6_TIME_EXCEED_TRANSIT, 0); 16953541Sshin return; 17053541Sshin } 17153541Sshin ip6->ip6_hlim -= IPV6_HLIMDEC; 17253541Sshin 17362587Sitojun /* 17462587Sitojun * Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU - 17562587Sitojun * size of IPv6 + ICMPv6 headers) bytes of the packet in case 17662587Sitojun * we need to generate an ICMP6 message to the src. 17762587Sitojun * Thanks to M_EXT, in most cases copy will not occur. 17862587Sitojun * 17962587Sitojun * It is important to save it before IPsec processing as IPsec 18062587Sitojun * processing may modify the mbuf. 18162587Sitojun */ 18262587Sitojun mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN)); 18362587Sitojun 18463256Sitojun#ifdef IPSEC 18553541Sshin /* get a security policy for this packet */ 186120913Sume sp = ipsec6_getpolicybyaddr(m, IPSEC_DIR_OUTBOUND, 187120913Sume IP_FORWARDING, &error); 18853541Sshin if (sp == NULL) { 18953541Sshin ipsec6stat.out_inval++; 19053541Sshin ip6stat.ip6s_cantforward++; 19162587Sitojun if (mcopy) { 19262587Sitojun#if 0 19362587Sitojun /* XXX: what icmp ? */ 19462587Sitojun#else 19562587Sitojun m_freem(mcopy); 19662587Sitojun#endif 19762587Sitojun } 19853541Sshin m_freem(m); 19953541Sshin return; 20053541Sshin } 20153541Sshin 20253541Sshin error = 0; 20353541Sshin 20453541Sshin /* check policy */ 20553541Sshin switch (sp->policy) { 20653541Sshin case IPSEC_POLICY_DISCARD: 20753541Sshin /* 20853541Sshin * This packet is just discarded. 20953541Sshin */ 21053541Sshin ipsec6stat.out_polvio++; 21153541Sshin ip6stat.ip6s_cantforward++; 21253541Sshin key_freesp(sp); 21362587Sitojun if (mcopy) { 21462587Sitojun#if 0 21562587Sitojun /* XXX: what icmp ? */ 21662587Sitojun#else 21762587Sitojun m_freem(mcopy); 21862587Sitojun#endif 21962587Sitojun } 22053541Sshin m_freem(m); 22153541Sshin return; 22253541Sshin 22353541Sshin case IPSEC_POLICY_BYPASS: 22453541Sshin case IPSEC_POLICY_NONE: 22553541Sshin /* no need to do IPsec. */ 22653541Sshin key_freesp(sp); 22753541Sshin goto skip_ipsec; 22862587Sitojun 22953541Sshin case IPSEC_POLICY_IPSEC: 23053541Sshin if (sp->req == NULL) { 23153541Sshin /* XXX should be panic ? */ 23253541Sshin printf("ip6_forward: No IPsec request specified.\n"); 23353541Sshin ip6stat.ip6s_cantforward++; 23453541Sshin key_freesp(sp); 23562587Sitojun if (mcopy) { 23662587Sitojun#if 0 23762587Sitojun /* XXX: what icmp ? */ 23862587Sitojun#else 23962587Sitojun m_freem(mcopy); 24062587Sitojun#endif 24162587Sitojun } 24253541Sshin m_freem(m); 24353541Sshin return; 24453541Sshin } 24553541Sshin /* do IPsec */ 24653541Sshin break; 24753541Sshin 24853541Sshin case IPSEC_POLICY_ENTRUST: 24953541Sshin default: 25053541Sshin /* should be panic ?? */ 25153541Sshin printf("ip6_forward: Invalid policy found. %d\n", sp->policy); 25253541Sshin key_freesp(sp); 25353541Sshin goto skip_ipsec; 25453541Sshin } 25553541Sshin 25653541Sshin { 257122062Sume struct ipsecrequest *isr = NULL; 25853541Sshin struct ipsec_output_state state; 25953541Sshin 26053541Sshin /* 261122062Sume * when the kernel forwards a packet, it is not proper to apply 262122062Sume * IPsec transport mode to the packet is not proper. this check 263122062Sume * avoid from this. 264122062Sume * at present, if there is even a transport mode SA request in the 265122062Sume * security policy, the kernel does not apply IPsec to the packet. 266122062Sume * this check is not enough because the following case is valid. 267122062Sume * ipsec esp/tunnel/xxx-xxx/require esp/transport//require; 268122062Sume */ 269122062Sume for (isr = sp->req; isr; isr = isr->next) { 270122062Sume if (isr->saidx.mode == IPSEC_MODE_TRANSPORT) 271122062Sume goto skip_ipsec; 272122062Sume } 273122062Sume 274122062Sume /* 27553541Sshin * All the extension headers will become inaccessible 27653541Sshin * (since they can be encrypted). 27753541Sshin * Don't panic, we need no more updates to extension headers 27853541Sshin * on inner IPv6 packet (since they are now encapsulated). 27953541Sshin * 28053541Sshin * IPv6 [ESP|AH] IPv6 [extension headers] payload 28153541Sshin */ 28253541Sshin bzero(&state, sizeof(state)); 28353541Sshin state.m = m; 28453541Sshin state.ro = NULL; /* update at ipsec6_output_tunnel() */ 28553541Sshin state.dst = NULL; /* update at ipsec6_output_tunnel() */ 28653541Sshin 28753541Sshin error = ipsec6_output_tunnel(&state, sp, 0); 28853541Sshin 28953541Sshin m = state.m; 29053541Sshin key_freesp(sp); 29153541Sshin 29253541Sshin if (error) { 29353541Sshin /* mbuf is already reclaimed in ipsec6_output_tunnel. */ 29453541Sshin switch (error) { 29553541Sshin case EHOSTUNREACH: 29653541Sshin case ENETUNREACH: 29753541Sshin case EMSGSIZE: 29853541Sshin case ENOBUFS: 29953541Sshin case ENOMEM: 30053541Sshin break; 30153541Sshin default: 30253541Sshin printf("ip6_output (ipsec): error code %d\n", error); 303120913Sume /* FALLTHROUGH */ 30453541Sshin case ENOENT: 30553541Sshin /* don't show these error codes to the user */ 30653541Sshin break; 30753541Sshin } 30853541Sshin ip6stat.ip6s_cantforward++; 30962587Sitojun if (mcopy) { 31062587Sitojun#if 0 31162587Sitojun /* XXX: what icmp ? */ 31262587Sitojun#else 31362587Sitojun m_freem(mcopy); 31462587Sitojun#endif 31562587Sitojun } 31653541Sshin m_freem(m); 31753541Sshin return; 31853541Sshin } 319122062Sume 320122062Sume /* adjust pointer */ 321122062Sume ip6 = mtod(m, struct ip6_hdr *); 322122062Sume dst = (struct sockaddr_in6 *)state.dst; 323122062Sume rt = state.ro ? state.ro->ro_rt : NULL; 324122062Sume if (dst != NULL && rt != NULL) 325122062Sume ipsecrt = 1; 32653541Sshin } 32753541Sshin skip_ipsec: 32863256Sitojun#endif /* IPSEC */ 32953541Sshin 330122062Sume#ifdef IPSEC 331122062Sume if (ipsecrt) 332122062Sume goto skip_routing; 333122062Sume#endif 334122062Sume 33578064Sume dst = (struct sockaddr_in6 *)&ip6_forward_rt.ro_dst; 33653541Sshin if (!srcrt) { 337120913Sume /* ip6_forward_rt.ro_dst.sin6_addr is equal to ip6->ip6_dst */ 33853541Sshin if (ip6_forward_rt.ro_rt == 0 || 33953541Sshin (ip6_forward_rt.ro_rt->rt_flags & RTF_UP) == 0) { 34053541Sshin if (ip6_forward_rt.ro_rt) { 34153541Sshin RTFREE(ip6_forward_rt.ro_rt); 34253541Sshin ip6_forward_rt.ro_rt = 0; 34353541Sshin } 344120913Sume 34553541Sshin /* this probably fails but give it a try again */ 34653541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, 34753541Sshin RTF_PRCLONING); 34853541Sshin } 34962587Sitojun 35053541Sshin if (ip6_forward_rt.ro_rt == 0) { 35153541Sshin ip6stat.ip6s_noroute++; 35278064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 35362587Sitojun if (mcopy) { 35462587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 35562587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 35662587Sitojun } 35762587Sitojun m_freem(m); 35853541Sshin return; 35953541Sshin } 36053541Sshin } else if ((rt = ip6_forward_rt.ro_rt) == 0 || 361120913Sume !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst->sin6_addr)) { 36253541Sshin if (ip6_forward_rt.ro_rt) { 36353541Sshin RTFREE(ip6_forward_rt.ro_rt); 36453541Sshin ip6_forward_rt.ro_rt = 0; 36553541Sshin } 36653541Sshin bzero(dst, sizeof(*dst)); 36753541Sshin dst->sin6_len = sizeof(struct sockaddr_in6); 36853541Sshin dst->sin6_family = AF_INET6; 36953541Sshin dst->sin6_addr = ip6->ip6_dst; 37053541Sshin 37153541Sshin rtalloc_ign((struct route *)&ip6_forward_rt, RTF_PRCLONING); 37253541Sshin if (ip6_forward_rt.ro_rt == 0) { 37353541Sshin ip6stat.ip6s_noroute++; 37478064Sume in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_noroute); 37562587Sitojun if (mcopy) { 37662587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 37762587Sitojun ICMP6_DST_UNREACH_NOROUTE, 0); 37862587Sitojun } 37962587Sitojun m_freem(m); 38053541Sshin return; 38153541Sshin } 38253541Sshin } 38353541Sshin rt = ip6_forward_rt.ro_rt; 384122062Sume#ifdef IPSEC 385122062Sume skip_routing:; 386122062Sume#endif 38762587Sitojun 38862587Sitojun /* 38962587Sitojun * Scope check: if a packet can't be delivered to its destination 39062587Sitojun * for the reason that the destination is beyond the scope of the 39162587Sitojun * source address, discard the packet and return an icmp6 destination 39262587Sitojun * unreachable error with Code 2 (beyond scope of source address). 39395023Ssuz * [draft-ietf-ipngwg-icmp-v3-02.txt, Section 3.1] 39462587Sitojun */ 395121315Sume if (in6_addr2zoneid(m->m_pkthdr.rcvif, &ip6->ip6_src, &srczone) || 396122062Sume in6_addr2zoneid(rt->rt_ifp, &ip6->ip6_src, &dstzone)) { 397122062Sume /* XXX: this should not happen */ 39862587Sitojun ip6stat.ip6s_cantforward++; 39962587Sitojun ip6stat.ip6s_badscope++; 400122062Sume m_freem(m); 401122062Sume return; 402122062Sume } 403122062Sume if (srczone != dstzone 404122062Sume#ifdef IPSEC 405122062Sume && !ipsecrt 406122062Sume#endif 407122062Sume ) { 408122062Sume ip6stat.ip6s_cantforward++; 409122062Sume ip6stat.ip6s_badscope++; 41062587Sitojun in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard); 41162587Sitojun 41262587Sitojun if (ip6_log_time + ip6_log_interval < time_second) { 41362587Sitojun ip6_log_time = time_second; 41462587Sitojun log(LOG_DEBUG, 41562587Sitojun "cannot forward " 41662587Sitojun "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 41762587Sitojun ip6_sprintf(&ip6->ip6_src), 41862587Sitojun ip6_sprintf(&ip6->ip6_dst), 41962587Sitojun ip6->ip6_nxt, 42062587Sitojun if_name(m->m_pkthdr.rcvif), if_name(rt->rt_ifp)); 42162587Sitojun } 42262587Sitojun if (mcopy) 42362587Sitojun icmp6_error(mcopy, ICMP6_DST_UNREACH, 42462587Sitojun ICMP6_DST_UNREACH_BEYONDSCOPE, 0); 42562587Sitojun m_freem(m); 42662587Sitojun return; 42762587Sitojun } 42862587Sitojun 429121283Sume if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) { 43053541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig); 43162587Sitojun if (mcopy) { 43262587Sitojun u_long mtu; 43363256Sitojun#ifdef IPSEC 43462587Sitojun struct secpolicy *sp; 43562587Sitojun int ipsecerror; 43662587Sitojun size_t ipsechdrsiz; 43762587Sitojun#endif 43862587Sitojun 439121283Sume mtu = IN6_LINKMTU(rt->rt_ifp); 44063256Sitojun#ifdef IPSEC 44162587Sitojun /* 44262587Sitojun * When we do IPsec tunnel ingress, we need to play 443122062Sume * with the link value (decrement IPsec header size 44462587Sitojun * from mtu value). The code is much simpler than v4 44562587Sitojun * case, as we have the outgoing interface for 44662587Sitojun * encapsulated packet as "rt->rt_ifp". 44762587Sitojun */ 44862587Sitojun sp = ipsec6_getpolicybyaddr(mcopy, IPSEC_DIR_OUTBOUND, 44962587Sitojun IP_FORWARDING, &ipsecerror); 45062587Sitojun if (sp) { 45162587Sitojun ipsechdrsiz = ipsec6_hdrsiz(mcopy, 45262587Sitojun IPSEC_DIR_OUTBOUND, NULL); 45362587Sitojun if (ipsechdrsiz < mtu) 45462587Sitojun mtu -= ipsechdrsiz; 45562587Sitojun } 45662587Sitojun 45762587Sitojun /* 45862587Sitojun * if mtu becomes less than minimum MTU, 45962587Sitojun * tell minimum MTU (and I'll need to fragment it). 46062587Sitojun */ 46162587Sitojun if (mtu < IPV6_MMTU) 46262587Sitojun mtu = IPV6_MMTU; 46362587Sitojun#endif 46462587Sitojun icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu); 46562587Sitojun } 46662587Sitojun m_freem(m); 46753541Sshin return; 468120913Sume } 46953541Sshin 47053541Sshin if (rt->rt_flags & RTF_GATEWAY) 47153541Sshin dst = (struct sockaddr_in6 *)rt->rt_gateway; 47253541Sshin 47353541Sshin /* 47453541Sshin * If we are to forward the packet using the same interface 47553541Sshin * as one we got the packet from, perhaps we should send a redirect 47653541Sshin * to sender to shortcut a hop. 47753541Sshin * Only send redirect if source is sending directly to us, 47853541Sshin * and if packet was not source routed (or has any options). 47953541Sshin * Also, don't send redirect if forwarding using a route 48053541Sshin * modified by a redirect. 48153541Sshin */ 48253541Sshin if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && 483122062Sume#ifdef IPSEC 484122062Sume !ipsecrt && 485122062Sume#endif 48678064Sume (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) { 48778064Sume if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) != 0) { 48878064Sume /* 48978064Sume * If the incoming interface is equal to the outgoing 49078064Sume * one, and the link attached to the interface is 49178064Sume * point-to-point, then it will be highly probable 49278064Sume * that a routing loop occurs. Thus, we immediately 49378064Sume * drop the packet and send an ICMPv6 error message. 49478064Sume * 49578064Sume * type/code is based on suggestion by Rich Draves. 49678064Sume * not sure if it is the best pick. 49778064Sume */ 49878064Sume icmp6_error(mcopy, ICMP6_DST_UNREACH, 49978064Sume ICMP6_DST_UNREACH_ADDR, 0); 50078064Sume m_freem(m); 50178064Sume return; 50278064Sume } 50353541Sshin type = ND_REDIRECT; 50478064Sume } 50553541Sshin 50653541Sshin /* 50753541Sshin * Check with the firewall... 50853541Sshin */ 50966303Sume if (ip6_fw_enable && ip6_fw_chk_ptr) { 51053541Sshin u_short port = 0; 51153541Sshin /* If ipfw says divert, we have to just drop packet */ 51253541Sshin if ((*ip6_fw_chk_ptr)(&ip6, rt->rt_ifp, &port, &m)) { 51353541Sshin m_freem(m); 51453541Sshin goto freecopy; 51553541Sshin } 51653541Sshin if (!m) 51753541Sshin goto freecopy; 51853541Sshin } 51953541Sshin 52062587Sitojun /* 52162587Sitojun * Fake scoped addresses. Note that even link-local source or 52262587Sitojun * destinaion can appear, if the originating node just sends the 52362587Sitojun * packet to us (without address resolution for the destination). 52462587Sitojun * Since both icmp6_error and icmp6_redirect_output fill the embedded 52578064Sume * link identifiers, we can do this stuff after making a copy for 52678064Sume * returning an error. 52762587Sitojun */ 52862587Sitojun if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) { 52962587Sitojun /* 53062587Sitojun * See corresponding comments in ip6_output. 53162587Sitojun * XXX: but is it possible that ip6_forward() sends a packet 53262587Sitojun * to a loopback interface? I don't think so, and thus 53362587Sitojun * I bark here. (jinmei@kame.net) 53462587Sitojun * XXX: it is common to route invalid packets to loopback. 53562587Sitojun * also, the codepath will be visited on use of ::1 in 53662587Sitojun * rthdr. (itojun) 53762587Sitojun */ 53862587Sitojun#if 1 53962587Sitojun if (0) 54062587Sitojun#else 54162587Sitojun if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0) 54262587Sitojun#endif 54362587Sitojun { 54462587Sitojun printf("ip6_forward: outgoing interface is loopback. " 545120913Sume "src %s, dst %s, nxt %d, rcvif %s, outif %s\n", 546120913Sume ip6_sprintf(&ip6->ip6_src), 547120913Sume ip6_sprintf(&ip6->ip6_dst), 548120913Sume ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif), 549120913Sume if_name(rt->rt_ifp)); 55062587Sitojun } 55162587Sitojun 55278064Sume /* we can just use rcvif in forwarding. */ 55378064Sume origifp = m->m_pkthdr.rcvif; 55462587Sitojun } 55562587Sitojun else 55662587Sitojun origifp = rt->rt_ifp; 55778064Sume /* 55878064Sume * clear embedded scope identifiers if necessary. 55978064Sume * in6_clearscope will touch the addresses only when necessary. 56078064Sume */ 56178064Sume in6_clearscope(&ip6->ip6_src); 56278064Sume in6_clearscope(&ip6->ip6_dst); 56362587Sitojun 56484994Sdarrenr#ifdef PFIL_HOOKS 56584994Sdarrenr /* 56684994Sdarrenr * Run through list of hooks for output packets. 56784994Sdarrenr */ 568120593Ssam error = pfil_run_hooks(&inet6_pfil_hook, &m, rt->rt_ifp, PFIL_OUT); 569120593Ssam if (error != 0) 570120593Ssam goto senderr; 571120386Ssam if (m == NULL) 572120386Ssam goto freecopy; 573120386Ssam ip6 = mtod(m, struct ip6_hdr *); 57484994Sdarrenr#endif /* PFIL_HOOKS */ 57584994Sdarrenr 57662587Sitojun error = nd6_output(rt->rt_ifp, origifp, m, dst, rt); 57753541Sshin if (error) { 57853541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard); 57953541Sshin ip6stat.ip6s_cantforward++; 58053541Sshin } else { 58153541Sshin ip6stat.ip6s_forward++; 58253541Sshin in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward); 58353541Sshin if (type) 58453541Sshin ip6stat.ip6s_redirectsent++; 58553541Sshin else { 58653541Sshin if (mcopy) 58753541Sshin goto freecopy; 58853541Sshin } 58953541Sshin } 590120913Sume 591120593Ssam#ifdef PFIL_HOOKS 592120593Ssamsenderr: 593120593Ssam#endif 59453541Sshin if (mcopy == NULL) 59553541Sshin return; 59653541Sshin switch (error) { 59753541Sshin case 0: 59853541Sshin if (type == ND_REDIRECT) { 59953541Sshin icmp6_redirect_output(mcopy, rt); 60053541Sshin return; 60153541Sshin } 60253541Sshin goto freecopy; 60353541Sshin 60453541Sshin case EMSGSIZE: 60553541Sshin /* xxx MTU is constant in PPP? */ 60653541Sshin goto freecopy; 60753541Sshin 60853541Sshin case ENOBUFS: 60953541Sshin /* Tell source to slow down like source quench in IP? */ 61053541Sshin goto freecopy; 61153541Sshin 61253541Sshin case ENETUNREACH: /* shouldn't happen, checked above */ 61353541Sshin case EHOSTUNREACH: 61453541Sshin case ENETDOWN: 61553541Sshin case EHOSTDOWN: 61653541Sshin default: 61753541Sshin type = ICMP6_DST_UNREACH; 61853541Sshin code = ICMP6_DST_UNREACH_ADDR; 61953541Sshin break; 62053541Sshin } 62153541Sshin icmp6_error(mcopy, type, code, 0); 62253541Sshin return; 62353541Sshin 62453541Sshin freecopy: 62553541Sshin m_freem(mcopy); 62653541Sshin return; 62753541Sshin} 628